Automatic spring forming machines are known. For example, Taiwanese patent publication No. 129967 discloses a CNC spring forming machine which is shown in FIGS. 10 and 11 of the attached drawings. This prior art spring forming machine comprises a wire feed device to feed a length of wire into the spring forming machine to be worked on by a plurality of spring formation tools which are mounted on separate tool slides to be driven and controlled by cam devices under the control of a microcomputer control unit. A gear transmission system is provided to drive the cam devices. The microcomputer control unit controls the movements of the tools and the feed of the wire to form springs with the spring formation tools in a automatic manner. This provides an automatic, high efficiency spring forming machine.
One of the disadvantages of such a prior art spring forming machine structure is that the movement of the tools A (FIG. 11), the speeds and the dead intervals thereof are all controlled by the cam devices B (FIG. 11). A change in the manufacturing process requires changeover and trial-and-error tests of new cam devices. This complicates the manufacturing of springs of different types, especially for small quantity, great variety manufacturing. Further, such a prior art machine structure only allows the spring formation tools to move or feed in a linear manner within a tool holder C (FIG. 11) and no curved motion of the tools is possible. This limits the capability of the spring forming machine.
It is therefore desirable to provide a spring formation apparatus which overcomes the above-mentioned deficiencies.